In the prior art, an interventional cardiac valve generally includes a compressible valve stent and a plurality of leaflets, wherein the valve stent has good biological compatibility, and can be positioned at a corresponding cardiac valve location safely, stably, and reliably.
A main body of a valve stent is usually a rhombic unit structure, which is configured to meet the requirement of compressibility. However, the rhombic unit structure may form independent rhombic vertices, and these rhombic vertices existing in isolation are usually sharp. During the use process of the valve stent, there is a risk that the rhombic vertices existing in isolation pierce a sheath.
If the rhombic vertices existing in isolation are gathered at an end portion of the valve stent, the risk of piercing is relatively low. However, in order to be fit for particular structures of different valves of hearts, valve stents used in different positions have different structures.
Taking a pulmonary valve as an example, in order to make the location of the valve at the main pulmonary artery more stable, the valve stent is further provided with a flared section located at a branch location of the main pulmonary artery, that is, the rhombic units structure at the end portion of the valve stent are extended further in an axial direction of the valve stent and expanded in a radial direction of the valve stent, such that this portion is softer and can resiliently match with a blood vessel wall, thereby preventing the blood vessel wall from being stabbed or even pierced. However, the changes of the structure on the end portion may cause some vertices of the rhombic unit structures of the valve stent, which exist in isolation, to be exposed.
For example, a Chinese patent application publication CN102961199A discloses a pulmonary artery valve stent which can prevent displacements. The pulmonary artery valve stent includes a valve suture section, an artificial valve connected with the valve suture section, and a position limiting structure connected with a distal end of the valve suture section. The valve suture section is located in a right ventricular outflow tract or a main body of the pulmonary artery after being released, and a vertex portion of the position limiting structure abuts against an intersecting portion of the main body of the pulmonary artery and a branch of the pulmonary artery after being released, thereby providing an axial limiting function. In this patent document, the valve suture section is formed by a plurality of rhombic structure units; when the distal end of the valve suture section is connected with the position limiting structure, some rhombic vertices of the rhombic structure existing in isolation may remain, and these rhombic vertices existing in isolation are potential safety hazards during the use process.
For another example, a Chinese patent CN101951858B discloses a funnel shaped throttling device. As shown in FIG. 1, the funnel shaped throttling device includes a middle portion having rhombic grid structures, and two end portions of flared shape connected to two ends of the middle portion respectively. The middle rhombic grid structures has a plurality of rhombic vertices 10 existing in isolation, may cause much inconvenience during operation process.
When a valve stent is compressed inwards a sheath pipe, the rhombic vertices existing in isolation will become spines. The spines are prone to stab the sheath pipe when passing through complex and curved anatomic paths in a human body. In the subsequent process of releasing valve, they may also result in too much resistance and pierce the sheath pipe, and thereby cause the valve to be unable to release successfully; in extreme cases, they may stab or even pierce blood vessel walls, and then cause great harm to patients.